Ecological site group DX035X01EESG05
Green River Desert - Shallow Shrublands and Woodlands - low elevation
Last updated: 09/01/2021
Accessed: 05/02/2024
Ecological site group description
Key Characteristics
- Green River Desert
- Shallow Shrublands and Woodlands
- Low Elevation MAST > 54 degrees F.
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
Physiography
This group of ecological sites is located on dissected pediments, escarpments, ledges, hillslopes on structural benches, benches, rolling ridges, dissected cuestas, structural benches, mesas, hillslopes, and canyons. Runoff is variable and ranges from medium to very high. Slopes typically range from 1-30%, but in some areas, slopes are as steep as 60%. Elevations are generally 3700-6800 feet.
Climate
The climate is characterized by hot summers and cool to warm winters. Large fluctuations in daily temperatures are common. The mean annual air temperature ranges from 40 to 57 degrees Fahrenheit. Approximately 65–70% of precipitation occurs as rain from March through October. On the average, April, May, and June are the driest months and August, September, and October are the wettest months. Precipitation is extremely variable from month to month and from year to year. Much of the precipitation occurs as convection thunderstorms. Average annual precipitation is 5 to 12 inches. Snow packs are generally light and not persistent.
Soil features
The soils in these ecological sites are very shallow or shallow to bedrock and well drained to somewhat excessively well drained. They formed in eolian deposits over residuum from sandstone and interbedded sandstone and shale. Surface textures range from loamy sands to fine sandy loams with 0 to 40 percent rock fragments, usually gravel or channers. Subsurface textures are generally similar but may include loams and sands. Typically, these soils are calcareous and nonsaline or slightly saline. Available water holding capacity is 0.5 to 3 inches due to restricted soil depth. In relatively undisturbed areas, a pinnacled biological soil crust is present, but may be discontinuous.
Vegetation dynamics
The dominant aspect of the plant communities on the ecological sites in this group is a blackbrush shrubland. A sparse overstory of Utah juniper and pinyon pine may be present in areas with more than 10 inches of annual precipitation. Herbaceous plants include a mix of cool and warm season perennial grasses and a few perennial forbs. There is little evidence to indicate that these sites historically maintained a short burn frequency. Large gaps between plants (very discontinuous fuels) in relic areas indicate that these sites may have historically rarely burned. Blackbrush appears to act as a paleo-endemic species on some sites in this MLRA and may not be able to reestablish itself after significant disturbance. Disturbances that reduce the presence of blackbrush result in an opportunity for invasive annuals to enter into the system and may produce a fuel load for fire to become an ecological driver. Cheatgrass, red brome, and Russian thistle are most likely to invade these sites.
This ecological site group has been grazed by domestic livestock since they were first introduced into the area around 1860. It is highly resistant to grazing due to the unpalatable nature of blackbrush and lack of forage plants. Improper livestock grazing including, season long grazing and\or heavy stocking rates, may cause these sites to depart from the reference plant communities.
Major Land Resource Area
MLRA 035X
Colorado Plateau
Subclasses
Stage
Provisional
Contributors
Vic Parslow
Keith Crossland
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